Liquid cooling pump motor low-temperature starting method

Abstract

The invention belongs to the field of motor control, and relates to a liquid cooling pump motor low-temperature starting method. After the liquid cooling pump receives a starting instruction, motor parameters are collected and judged, starting parameters at different temperatures are set, two-time pre-positioning, given-angle open-loop acceleration and closed-loop synchronization stages of a motor rotor are sequentially executed according to the corresponding starting parameters, and the motor is controlled to be started and run according to a rotating speed instruction. Wherein double closed-loop control of rotating speed closed-loop and current closed-loop is performed in the closed-loop synchronization stage, and rotating speed closed-loop control is performed by calculating and feeding back the actual rotating speed of the motor through the rotating speed of the motor. And if the generator overcurrent protection is triggered in any step of two-time pre-positioning, given-angle open-loop acceleration and closed-loop synchronization stages of the rotor, resetting the starting parameters, and starting the motor again for testing. Normal starting and working functions of the liquid cooling pump motor in a low-temperature environment can be realized, and the problem of starting failure or stalling caused by a traditional motor starting mode can be solved.

Description

Technical Field

[0001] The invention belongs to the field of motor control and relates to a low-temperature starting method for a liquid-cooling pump motor. Background Art

[0002] The liquid cooling pump is a crucial component of an aircraft's liquid cooling system. It utilizes liquid cooling to dissipate heat, transferring coolant from the oil-gas separator through pipes. The pump's motor, installed within the pump's core, drives the impeller, causing the coolant to form a high-speed rotating fluid within the pump body. This fluid is then transported to the equipment requiring cooling, removing heat and ensuring its proper operation.

[0003] To meet environmental adaptability requirements, liquid-cooled pump motors must be able to start and operate normally in ambient temperatures ranging from -55°C to 70°C. However, coolant flowability decreases and viscosity increases in low-temperature environments. Excessive viscosity can hinder coolant circulation, hindering the starting of the liquid-cooled pump motor. Traditional motor starting methods typically only consider starting performance parameters at room and high temperatures and cannot meet the requirements for normal starting in low-temperature environments. Summary of the Invention

[0004] Purpose of the Invention

[0005] A low-temperature starting method for a liquid-cooled pump motor is provided, which can meet the adaptability requirements of the liquid-cooled pump motor in low-temperature ground working environments under extreme temperatures of -55°C. This method solves the problem of existing motor starting methods that prevent the liquid-cooled pump motor from starting normally due to excessive coolant viscosity in low-temperature environments.

[0006] Technical Solution

[0007] A method for low-temperature starting of a liquid-cooled pump motor. Upon receiving a start command, the liquid-cooled pump collects and determines motor parameters and sets start parameters for different temperatures. Based on the corresponding start parameters, the pump sequentially executes two stages of motor rotor pre-positioning, open-loop acceleration at a given angle, and closed-loop synchronization, controlling the motor to start and operate according to the speed command. The closed-loop synchronization stage implements dual closed-loop control of speed and current, requiring feedback of the actual motor speed through motor speed calculation for closed-loop speed control. If the motor overcurrent protection is triggered during any of the two rotor pre-positioning, open-loop acceleration at a given angle, and closed-loop synchronization stages, the start parameters are reset and the motor is restarted for testing.

[0008] Furthermore, the following process is included:

[0009] Step 1: Start parameter setting;

[0010] Step 2: Pre-position the motor rotor for the first time;

[0011] Step 3: Pre-position the motor rotor for the second time;

[0012] Step 4: Accelerate the given open-loop angle;

[0013] Step 5: Closed-loop synchronization phase;

[0014] Step 6: Calculate the motor speed;

[0015] Step 7: Motor overcurrent detection and protection.

[0016] Furthermore, in step 1, when the liquid-cooling pump motor receives the start-up command, the liquid-cooling pump motor parameters are collected and initialized, and the motor temperature at the start-up time is determined, and two sets of different parameters are set: low-temperature start-up parameters and normal temperature / high-temperature start-up parameters. Only one set of start-up parameters is selected, and the first pre-positioning duration t1 and the first pre-positioning voltage vector amplitude U1 are passed to step 2, and the second pre-positioning duration t2 and the second pre-positioning voltage vector amplitude U2 are passed to step 3, and the open-loop starting current amplitude I, the open-loop acceleration coefficient Δn and the open-loop running time t3 are passed to step 4, the speed acceleration and deceleration ramp value ramp is passed to step 5, and the overcurrent protection threshold Imax is passed to step 7.

[0017] Furthermore, in step 2, according to the first pre-positioning duration t1 and the first pre-positioning voltage vector amplitude U1 set in step 1, a voltage vector of a fixed direction is applied to the stator winding of the motor, and the stator winding current generates an electromagnetic torque of a fixed direction to rotate the motor rotor to a predetermined position;

[0018] Furthermore, in step 3, according to the second pre-positioning duration t2 and the second pre-positioning voltage vector amplitude U2 set in step 1, a voltage vector of another fixed direction is applied to the stator winding of the motor, and the stator winding current generates an electromagnetic torque of another fixed direction to rotate the motor rotor to a predetermined position;

[0019] Furthermore, in step 4, according to the open-loop starting current amplitude I, the open-loop acceleration coefficient Δn, and the open-loop running time t3 set in step 1, a current closed-loop control is performed to apply a rotating current vector to the stator winding of the motor to drive the motor to rotate to a predetermined open-loop speed;

[0020] Furthermore, in step 5, based on the speed acceleration / deceleration ramp value ramp set in step 1 and the motor rotation speed calculated in step 6, a speed closed-loop control and a current closed-loop control are performed to control the liquid cooling pump motor to operate within a specified speed range according to the fixed acceleration / deceleration ramp;

[0021] Furthermore, step 6 is used to calculate the motor rotation speed and pass it to step 5 to complete the motor speed and current dual closed-loop control;

[0022] Furthermore, in step 7, different overcurrent protection thresholds are set for overcurrent protection at different motor temperatures based on the overcurrent protection threshold Imax parameter set in step 1. This is used to monitor the current values during motor startup and operation in steps 2, 3, 4, and 5 to prevent product damage caused by overcurrent faults. If overcurrent protection is triggered or the motor fails to start, the process proceeds to step 1 to reset the startup parameters and protection thresholds.

[0023] Furthermore, the fixed direction differs from another fixed direction by 90°.

[0024] Furthermore, if any of step 2, step 3, step 4 or step 5 triggers the overcurrent protection of step 7, then return to step 1, reset the starting parameters, and start the motor again.

[0025] Furthermore, in step 1, during the first low-temperature test, due to the unknown coolant viscosity, the startup parameters are directly set to normal temperature / high temperature startup parameters.

[0026] The beneficial effects of this application are:

[0027] Compared with traditional motor starting methods, the present invention has higher safety and feasibility. At the same time, the method can judge different ambient temperatures at the starting time, automatically adjust the starting parameters, improve the starting reliability, and has overcurrent detection and protection, which can avoid the large starting torque caused by excessive coolant viscosity in extreme low temperature environments and thus the large starting current phenomenon, further improving the reliability of motor starting.

[0028] This invention not only ensures normal startup and operation of the liquid-cooled pump motor in low-temperature environments, but also resolves startup failures and stalls caused by traditional motor starting methods. It also balances startup performance at both normal and high temperatures, meeting onboard startup requirements, enabling rapid heat dissipation and cooling, and improving product mission reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Flowchart of low temperature starting method for liquid cooling pump motor;

[0030] Figure 2 Principle block diagram of initial positioning and open-loop starting;

[0031] Figure 3 Open loop speed versus time graph;

[0032] Figure 4 Block diagram of closed-loop synchronization stage control principle. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the implementation of the present invention clearer, the technical solutions in the embodiments of the present invention will be described in more detail below in conjunction with the embodiments of the present invention. In the examples, the same or similar reference numerals throughout represent the same or similar originals or elements with the same or similar functions. The described embodiments are part of the embodiments of the present invention, not all of the embodiments. The embodiments described below by reference are illustrative and intended to be used to explain the present invention, and should not be understood as limiting the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. The following is a detailed description in conjunction with the embodiments of the present invention.

[0034] This invention provides a low-temperature starting method for a liquid-cooled pump motor. This method aims to address the problem of poor coolant flow and increased viscosity in the liquid-cooled pump pipeline at low temperatures, which significantly increases the motor starting torque and causes start failure or stalling in traditional motor starting methods. While the method shares the same fundamental principles as traditional motor starting methods, it differs in its application scenarios and methods.

[0035] The core invention of the scheme includes starting parameter setting (1), first motor rotor pre-positioning (2), second motor rotor pre-positioning (3), given open-loop angle acceleration (4), closed-loop synchronization stage (5), motor speed calculation (6), and motor overcurrent detection and protection (7). The core function of the scheme is to judge the different motor temperature values when the liquid-cooled pump motor starts, set the starting parameters (1), set low-temperature parameters or normal temperature / high temperature parameters to perform the first motor rotor pre-positioning (2), the second motor rotor pre-positioning (3), given open-loop angle acceleration (4), and closed-loop synchronization stage (5) control. In addition, the motor overcurrent detection and protection (7) ensures the safe and reliable operation of the liquid-cooled pump motor. The scheme can realize the normal starting and working function of the liquid-cooled pump motor in a low-temperature environment, while taking into account the starting performance requirements of the liquid-cooled pump motor in a normal temperature / high temperature environment.

[0036] 1. The method comprises the following steps: setting the starting parameters (1), pre-positioning the motor rotor for the first time (2), pre-positioning the motor rotor for the second time (3), accelerating at a given open-loop angle (4), a closed-loop synchronization stage (5), calculating the motor speed (6), and detecting and protecting the motor overcurrent (7);

[0037] 2. Startup parameter setting (1), which is used to collect and initialize the parameters of the liquid cooling pump motor when the liquid cooling pump is powered on, and to judge different motor temperatures at the startup time, set different startup parameters and transmit them to the first pre-positioning of the motor rotor (2), the second pre-positioning of the motor rotor (3), the given open-loop angle acceleration (4), the closed-loop synchronization stage (5) and the motor overcurrent detection and protection (7);

[0038] The first pre-positioning of the motor rotor (2) is used to determine the initial position of the rotor and apply a fixed direction voltage vector to the motor stator winding according to the parameters passed by the startup parameter setting (1). and the duration of positioning time t1;

[0039] The second pre-positioning of the motor rotor (3) is used to prevent the motor rotor from falling into the positioning blind zone during the first pre-positioning (2) of the motor rotor. According to the parameters transmitted by the starting parameter setting (1), another fixed direction voltage vector is applied to the motor stator winding. and the continuous positioning time t2;

[0040] A given open-loop angle acceleration (4) is used for current closed-loop control, and a rotating current vector is applied to the stator winding of the motor according to the parameters transmitted by the startup parameter setting (1), so as to drive the motor to rotate to a predetermined open-loop speed;

[0041] The closed-loop synchronization stage (5) is used for dual closed-loop control of speed closed-loop and current closed-loop, and controls the liquid cooling pump motor to operate within a specified speed range according to the parameters transmitted by the startup parameter setting (1) and the actual motor speed value obtained by the motor speed calculation (6), according to the fixed acceleration and deceleration ramps;

[0042] Motor speed calculation (6) is used to calculate the motor rotation speed and transmit it to the closed-loop synchronization stage (5) to complete the motor double closed-loop control;

[0043] Motor overcurrent detection and protection (7) is used to monitor the current value during motor startup and operation to prevent product damage caused by overcurrent faults. Based on the parameters transmitted in the startup parameter setting (1), different overcurrent protection thresholds are set for overcurrent protection at different motor temperatures. If overcurrent protection is triggered or the motor fails to start, the startup parameter setting (1) is executed to reset the startup parameters and protection thresholds.

[0044] 3. The starting parameter setting (1) sets different starting parameters and overcurrent protection thresholds in low temperature environment and normal temperature / high temperature environment. When the liquid cooling pump motor starts, the control unit obtains the temperature value of the liquid cooling pump motor through the platinum resistor installed on the motor winding. If the current temperature value is less than or equal to the low temperature starting threshold, the low temperature parameter is selected for starting. This parameter makes the open loop control efficiency low, and the heat energy generated when controlling the liquid cooling pump motor is high, so that the coolant temperature rises rapidly, the viscosity is reduced, and the reliability of the motor start is improved; if the current temperature value is greater than the low temperature starting threshold, the normal temperature / high temperature parameter is selected for starting. This parameter has a relatively high control efficiency, a short starting time, and a fast response speed, which meets the on-board starting performance requirements and realizes the function of rapid heat dissipation and cooling of the equipment. The starting parameters and overcurrent threshold are adjusted and determined according to the first pre-positioning of the motor rotor (2), the second pre-positioning of the motor rotor (3), the given open loop angle acceleration (4), and the motor current and temperature changes in the closed loop synchronization stage (5);

[0045] 4. The motor rotor is pre-positioned for the first time (2) by applying a voltage vector of a fixed direction to the motor stator winding. The stator winding current generates an electromagnetic torque of a fixed direction to rotate the motor rotor to a predetermined position. The amplitude and duration t1 are set by the startup parameter setting (1). The low temperature parameter setting has a high voltage amplitude, a long duration, a high heat energy generated, and reduces the viscosity of the coolant; the normal temperature / high temperature parameter setting has a low voltage amplitude, a short duration, a low heat energy generated, and a fast speed response. If the motor overcurrent detection and protection (7) is not triggered in this stage, the second pre-positioning of the motor rotor (3) is entered; otherwise, the startup parameter setting (1) is entered to reset the startup parameters;

[0046] 5. The second pre-positioning of the motor rotor (3) can effectively avoid the problem of the rotor falling into the positioning blind area and causing the motor to fail to start. Apply a voltage vector Vertical voltage vector And last for a period of time t2, so that the motor rotor rotates to the predetermined position. The applied voltage vector The amplitude and duration t2 are set by the startup parameter setting (1). The voltage amplitude of the low temperature parameter setting is high and the duration is longer, which continues to keep the motor in a heating state and further reduces the viscosity of the coolant; the voltage amplitude of the normal temperature / high temperature parameter setting is low and the duration is short, which generates low heat energy and has a fast speed response. If the motor overcurrent detection and protection (7) is not triggered in this stage, it will go to the given open loop angle acceleration (4); otherwise, it will go to the startup parameter setting (1) to reset the startup parameters;

[0047] 6. After the motor rotor initial position is pre-positioned, the motor enters the open-loop acceleration phase. By applying a constant q-axis current and the open-loop position angle generator θ * Apply a rotating current vector to the motor stator winding to drive the motor to rotate to a fixed speed. Among them, the open-loop position angle generator θ * Obtained by integrating the open-loop speed, the open-loop speed increases at a certain slope. The applied current amplitude, open-loop acceleration coefficient Δn and open-loop operation time are set by the startup parameter setting (1). The current amplitude of the low-temperature parameter setting is high, the open-loop acceleration coefficient is low, the acceleration time is long, the motor heating time is extended, and the viscosity of the coolant is further reduced; the current amplitude of the normal temperature / high temperature parameter setting is low, the open-loop acceleration coefficient is high, the acceleration time is short, and the speed response speed is fast. If the motor overcurrent detection and protection (7) is not triggered in this stage, it will enter the closed-loop synchronization stage (5); otherwise, it will enter the startup parameter setting (1) to reset the startup parameters;

[0048] 7. In the closed-loop synchronization stage (5), dual closed-loop control of speed closed-loop and current closed-loop is performed, so that the motor running speed is adjusted according to the speed command. The speed command is given in the form of a ramp, and its acceleration and deceleration ramp value is set by the starting parameter setting (1). The motor running speed is obtained by the motor speed calculation (6). The speed ramp set by the low-temperature parameter is small, which avoids the large load torque caused by the high viscosity of the coolant in the low-temperature extreme environment, thereby causing the large current phenomenon, ensuring that the motor can still maintain stable operation in a low-temperature environment; the speed ramp set by the normal temperature / high temperature parameter is large, and the speed response speed is fast, which can meet the starting performance requirements of the liquid cooling pump motor; if the motor overcurrent detection and protection (7) is not triggered in this stage, the liquid cooling pump motor starts successfully and the motor starting parameter value is fixed; otherwise, go to the starting parameter setting (1) to reset the starting parameters or overcurrent protection threshold;

[0049] 8. Motor overcurrent detection and protection (7) is used to monitor the current value during motor startup and operation to prevent product damage caused by overcurrent faults. If the motor overcurrent protection is triggered or the motor fails to start, the motor startup parameters or overcurrent protection threshold of the startup parameter setting (1) are readjusted according to the current value and motor temperature value during the test process until the liquid cooling pump motor starts successfully in the closed-loop synchronization stage (5) and operates according to the speed command requirements.

[0050] Each control stage is interconnected and complementary. By rationally applying various methods and exploring their internal connections, the method flow described in this application is formed around the purpose of the liquid-cooled pump motor starting effectively at low temperature, as shown in the following example: Figure 1 shown.

[0051] According to the method described in the present application, taking a certain type of liquid-cooled pump motor as an example, a motor starting test is performed at an ambient temperature of -55°C to 70°C.

[0052] Step 1: Start parameter settings

[0053] When the liquid cooling pump motor receives a start command, the parameters of the liquid cooling pump motor are collected and initialized, and the motor temperature at the start time is determined to set two different sets of parameters.

[0054] Table 1 lists known normal and high-temperature starting parameter values. When the ambient temperature is above 0°C, based on coolant performance and test results, conventional motor starting methods can stably start the motor. Based on the cooling rate requirements of the onboard equipment and the motor starting performance requirements, the normal and high-temperature starting parameter values can be fixed, with the low-temperature starting threshold set to 0°C.

[0055] Table 1 Normal temperature / high temperature startup parameters

[0056]

[0057]

[0058] The liquid-cooled pump motor was placed in an extremely low-temperature environment of -55°C to simulate the aircraft's worst-case operating conditions, and a low-temperature startup test was conducted. During the first low-temperature test, the startup parameters were set directly to normal / high temperature startup parameters due to unknown coolant viscosity.

[0059] Step 2: Pre-position the motor rotor for the first time

[0060] According to the first pre-positioning duration t1 (0.5s) and the first pre-positioning voltage vector amplitude U1 (2V) set in step 1, a fixed direction voltage vector is applied to the motor stator winding. The stator winding current generates a fixed direction electromagnetic torque to rotate the motor rotor to the predetermined position. The principle of initial positioning and open-loop starting is as follows: Figure 2 After testing, it was found that when the liquid cooling pump motor received the start command, the overcurrent protection of step 7 was triggered in step 2, and step 1 was executed again.

[0061] Step 1: Start parameter settings

[0062] According to the test results, the first pre-positioning duration and the first pre-positioning voltage vector amplitude are adjusted. The specific parameters are shown in Table 2.

[0063] Table 2 Low temperature start parameters (first adjustment)

[0064]

[0065]

[0066] Step 2: Pre-position the motor rotor for the first time

[0067] Apply a fixed-direction voltage vector to the motor stator windings based on the first pre-position duration t1 (2s) and the first pre-position voltage vector amplitude U1 (8V) set in step 1. After testing, if the test data in step 2 is normal and the overcurrent protection is not triggered when the liquid cooling pump motor receives the start command, proceed to step 3.

[0068] Step 3: Second pre-positioning of the motor rotor

[0069] Based on the second pre-positioning duration t2 (0.5s) and the second pre-positioning voltage vector amplitude U2 (2V) set in step 1, a voltage vector with another fixed direction is applied to the motor stator winding. The stator winding current generates an electromagnetic torque with another fixed direction, rotating the motor rotor to the predetermined position. The second fixed direction differs by 90° from the fixed direction in step 2. Testing has shown that when the liquid cooling pump motor receives a start command, the overcurrent protection in step 7 is triggered in step 3, and step 1 is re-executed.

[0070] Step 1: Start parameter settings

[0071] According to the test results, the second pre-positioning duration and the second pre-positioning voltage vector amplitude are reset. The specific parameters are shown in Table 3.

[0072] Table 3 Low temperature start parameters (second adjustment)

[0073]

[0074]

[0075] After testing, when the liquid cooling pump motor receives the start command, the test data in step 2 is normal and the overcurrent protection is not triggered, then execute step 3.

[0076] Step 3: Second pre-positioning of the motor rotor

[0077] Apply another fixed-direction voltage vector to the stator winding based on the second pre-position duration t2 (2s) and the second pre-position voltage vector amplitude U2 (8V) set in Step 1. After testing, if the test data in Step 3 is normal and the overcurrent protection is not triggered when the liquid-cooling pump motor receives the start command, proceed to Step 4.

[0078] Step 4: Accelerate the given open-loop angle

[0079] According to the open-loop starting current amplitude I (5A), open-loop acceleration coefficient Δn (1000rpm / s) and open-loop running time t3 (2s) set in step 1, current closed-loop control is performed, and a rotating current vector is applied to the motor stator winding to drive the motor to rotate to the predetermined open-loop speed (2000rpm). The relationship between the open-loop speed and time is as follows: Figure 3 After testing, it was found that when the liquid cooling pump motor received the start command, the overcurrent protection of step 7 was triggered during the open-loop acceleration of step 4, and step 1 was executed again.

[0080] Step 1: Start parameter settings

[0081] According to the test results, the open-loop acceleration related parameters and overcurrent protection threshold are reset. The specific parameters are shown in Table 4.

[0082] Table 4 Low temperature start parameters (third adjustment)

[0083]

[0084]

[0085] After testing, when the liquid cooling pump motor receives the start command, the test data of steps 2 to 4 are normal and the overcurrent protection is not triggered, then step 5 is executed.

[0086] Step 5, closed-loop synchronization phase;

[0087] According to the speed acceleration and deceleration ramp value (1750rpm / s) set in step 1 and the motor rotation speed calculated in step 6, the speed closed loop and current closed loop dual closed loop control are performed to control the liquid cooling pump motor to run at the rated speed of 10000rpm according to the fixed acceleration and deceleration ramp. The principle of the closed loop synchronization stage is as follows Figure 4 After testing, it was found that when the liquid cooling pump motor received the start command, the overcurrent protection of step 7 was triggered during the closed-loop synchronization phase of step 5, and step 1 was executed again.

[0088] Step 1: Start parameter settings

[0089] According to the test results, the speed acceleration and deceleration ramp values are reset. The specific parameters are shown in Table 5.

[0090] Table 5 Low temperature start parameters (fourth adjustment)

[0091]

[0092]

[0093] After testing, when the liquid cooling pump motor received the start command, the test data of steps 2 to 5 were normal, the overcurrent protection was not triggered, the liquid cooling pump motor started successfully, and the liquid cooling pump motor ran at the rated speed of 10,000 rpm.

[0094] Finally, the liquid-cooled pump motor was tested at a low-temperature start-up temperature of -55°C. The fixed motor low-temperature start-up parameter values are shown in Table 5, and the normal and high-temperature start-up parameter values are shown in Table 1. This met the environmental adaptability requirements, and the liquid-cooled pump motor product was able to start and operate normally in ambient temperatures ranging from -55°C to 70°C.

[0095] The present invention provides a low-temperature starting method for a liquid-cooled pump motor, which has the capabilities of stable starting in a wide temperature range, overcurrent protection, and current limiting.

[0096] The startup method provided by the embodiments of the present invention can meet the requirement for normal startup of the liquid-cooling pump motor at any ambient temperature between -55°C and 70°C. Furthermore, the method can automatically adjust startup parameters based on the different ambient temperatures at startup to achieve the startup performance requirements of the liquid-cooling pump system. Furthermore, the method provides overcurrent protection, preventing the high starting torque and resulting high starting current caused by excessive coolant viscosity in extremely low-temperature environments. This method offers high reliability and safety, and has been successfully verified in a product model.

[0097] In addition, unless otherwise defined, the technical or scientific terms used in the description of this application should have the ordinary meanings understood by those of ordinary skill in the art to which this application belongs. The words "upper," "lower," "left," "right," "center," "vertical," "horizontal," "inner," and "outer" used in the description of this application are only used to indicate relative directions or positional relationships, and do not imply that the device or component must have a specific orientation, be constructed, or operate in a specific orientation. When the absolute position of the described object changes, its relative positional relationship may also change accordingly. Therefore, they should not be understood as limitations on this application. The words "first," "second," "third," and similar terms used in the description of this application are used only for descriptive purposes to distinguish different components and should not be understood to indicate or imply relative importance. The words "one," "an," or "the" used in the description of this application should not be understood as absolute limitations on quantity, but should be understood as meaning the presence of at least one. The words "include" or "comprises" used in the description of this application mean that the element or object listed before the word includes the elements or objects listed after the word and their equivalents, but does not exclude other elements or objects.

[0098] In addition, it should be noted that, unless otherwise clearly stipulated and limited, the words "install", "connect", "connect" and similar terms used in the description of this application should be understood in a broad sense. For example, the connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, an indirect connection through an intermediate medium, or a connection between two components. Technical personnel in the field can understand their specific meanings in this application according to the specific circumstances.

[0099] The above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Within the spirit and principles of the present invention, any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes and apply it to other fields. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention, any modification, equivalent replacement, improvement, etc. made should be included in the scope of protection of the present invention.

Claims

1. A method for starting a liquid-cooled pump motor at low temperature, characterized in that: When the liquid cooling pump receives the start-up command, it collects and judges the motor parameters and sets the start-up parameters at different temperatures. According to the corresponding start-up parameters, the motor rotor is pre-positioned twice, the open-loop acceleration at a given angle, and the closed-loop synchronization stage is executed in sequence to control the motor to start and run according to the speed command. Among them, the closed-loop synchronization stage performs dual closed-loop control of speed and current, and the actual motor speed is fed back through motor speed calculation to perform speed closed-loop control. If any step of the rotor pre-positioning twice, open-loop acceleration at a given angle, and closed-loop synchronization stage triggers the motor overcurrent protection, the start-up parameters are reset and the motor is started again for testing.

2. The method according to claim 1, wherein The process includes the following: Step 1: Start parameter setting; Step 2: Pre-position the motor rotor for the first time; Step 3: Pre-position the motor rotor for the second time; Step 4: Accelerate the given open-loop angle; Step 5: Closed-loop synchronization phase; Step 6: Calculate the motor speed; Step 7: Motor overcurrent detection and protection.

3. The method according to claim 2, wherein Step 1: When the liquid-cooling pump motor receives the start command, the liquid-cooling pump motor parameters are collected and initialized, and the motor temperature at the start time is determined. Two different sets of parameters are set: low-temperature start parameters and normal temperature / high-temperature start parameters. Only one set of start parameters is selected, and the first pre-positioning duration t1 and the first pre-positioning voltage vector amplitude U1 are passed to step 2. The second pre-positioning duration t2 and the second pre-positioning voltage vector amplitude U2 are passed to step 3. The open-loop starting current amplitude I, the open-loop acceleration coefficient Δn and the open-loop running time t3 are passed to step 4. The speed acceleration and deceleration ramp value ramp is passed to step 5. The overcurrent protection threshold Imax is passed to step 7.

4. The method according to claim 3, wherein Step 2: According to the first pre-positioning duration t1 and the first pre-positioning voltage vector amplitude U1 set in step 1, a voltage vector with a fixed direction is applied to the stator winding of the motor. The stator winding current generates an electromagnetic torque with a fixed direction to rotate the motor rotor to a predetermined position.

5. The method according to claim 4, wherein Step 3: According to the second pre-positioning duration t2 and the second pre-positioning voltage vector amplitude U2 set in step 1, a voltage vector of another fixed direction is applied to the stator winding of the motor. The stator winding current generates an electromagnetic torque of another fixed direction to rotate the motor rotor to a predetermined position.

6. The method according to claim 5, wherein Step 4: Perform current closed-loop control based on the open-loop starting current amplitude I, open-loop acceleration coefficient Δn, and open-loop running time t3 set in step 1, apply a rotating current vector to the motor stator winding, and drive the motor to rotate to a predetermined open-loop speed.

7. The method according to claim 6, wherein In step 5, based on the speed acceleration / deceleration ramp value set in step 1 and the motor rotation speed calculated in step 6, dual closed-loop control of speed and current is performed to control the liquid cooling pump motor to operate within the specified speed range according to the fixed acceleration / deceleration ramp.

8. The method according to claim 7, wherein Step 6 is used to calculate the motor rotation speed and pass it to step 5 to complete the motor speed and current dual closed-loop control.

9. The method according to claim 8, wherein Step 7: Set different overcurrent protection thresholds for overcurrent protection at different motor temperatures based on the overcurrent protection threshold Imax parameter set in step 1. This is used to monitor the current values during motor startup and operation in steps 2, 3, 4, and 5 to prevent product damage caused by overcurrent faults. If the overcurrent protection is triggered or the motor fails to start, go to step 1 and reset the starting parameters and protection thresholds.

10. The method according to claim 9, wherein The fixed direction and the other fixed direction differ by 90°; if any of step 2, step 3, step 4 or step 5 triggers the overcurrent protection of step 7, then return to step 1, reset the starting parameters, and start the motor again; in step 1, during the first low-temperature test, due to the unknown coolant viscosity, the starting parameters are directly set to normal temperature / high temperature starting parameters.

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